-> -> How can SIO handle the port without an IRQ? Use polling?   
      
   -> It will; however, IIRC only if native OS/2 comm apps are using the   
   -> port.  Otherwise, you have to assign IRQs for DOS and Win64 comm   
      
   You're thinking of the DOS reflection IRQ provided by the vsio.sys   
   virtual device driver. The sio.sys physical device driver requires an   
   IRQ (possibly shared) for every port; it will not do polling.   
      
   I think Holger assumed that my IRQ 3 was a motherboard com port that   
   could be disabled in the BIOS.  That's not so; it's a PCI expansion card   
   that PCI assigns to IRQ 3, because there is no COM2 on the motherboard.   
      
   So I'm stuck with IRQ 3, like it or not. But as Mark said, sio2k may be   
   the problem.  I'll try again with SIO 1.60d.   
      
   --- PCBoard (R) v15.4/M 250 Beta   
    * Origin: Torres Vedras - Portugal (2:362/6)